This was a tricky instance for five mages. The first time I attempted when I had just turned 71 I wiped whilst killing the sets of three mobs on the first boss; mirror images weren’t going to last for them and the boss, and I couldn’t use polymorph on the undead. I am not proud.. but I found a way – burn down the boss and die, at least it worked! After a corpse run the room was clear and I could proceed to destroy the big spider:) easy peasy.
I wiped a few times on the last boss, it was a bit frustrating since I knew killing him meant level 21 for the guild! /cheer
I found it wasn’t possible to burn him down before he went underground, so it’s important not to take silly risks like not moving out the way of his AOE smash! Keep renewing mana shield and killing the trash as it hits the ground, in the end I could burn down the boss enough each time that he would go back underground before he could attack. Almost level 72 now..